(a) Technical Field
The present invention relates to a vehicle network system and method. More particularly, the present invention relates to a system and a method which can reduce waste of bandwidths and generation of an overhead, occurring in a message transferring process in a vehicle network structure in which a vehicle network such as controller area network (CAN), local interconnect network (LIN), and FlexRay and the Ethernet are connected and can allow an efficient communication between vehicle devices.
(b) Background Art
In recent years, as electronic technologies and communication technologies related to vehicles are being rapidly developed, the number and types of electronic systems applied to vehicles are increasing. For example, various demands on electronic systems such as an information and multimedia reproduction system, an artificial intelligence system, a rear side detection system, an around view monitoring (AVM) system, a lane departure warning system (LDWS), a collision avoidance system (CAS), and a traffic sign recognition system, in addition to a control system related to engine control or exhaust gas control and a safety system such as an airbag system in vehicles are continuously increasing.
In the electronic system, information collection units such as imaging devices (e.g., cameras, video cameras, etc.), various sensors, and high level/low level controller are connected via a communication network, and accordingly, a network structure which reduces separate dedicated wires for various functions while supporting the functions to configure a more efficient electronic system is required. In addition, protocols for providing a high bandwidth and increased flexibility, and a deterministic operation to configure the network structure are required, and various protocols defining wiring structures and communication standards for high level systems are recently being applied to vehicles.
Controller area network (CAN), local internet network (LIN), and FlexRay are representative protocols, and protocols that show various advantages in vehicles are being developed. Further, integrated network systems that connect protocols of different vehicles through conversion of data between a plurality of protocols, for integrating and managing the protocols are being developed.
In recent years, technologies for using the Ethernet in vehicle systems such as communication systems, control systems, and image providing systems are being proposed. In addition, various devices such as sensors, imaging devices (e.g., cameras, video cameras, etc.), and laser scanners are being used, and as the number of vehicle devices gradually increases, it is expected that the existing vehicle networks (CAN, LIN, and FlexRay) may not support the required bandwidths. In particular, the Ethernet audio video bridging (hereinafter, referred to as ‘AVB’) technology may be applied to developing vehicles, and the Ethernet AVB technology corresponds to protocols for transmitting string data such as audios and videos. In the vehicle electronic system that uses the Ethernet employing the AVB, vehicle devices are connected to communicate with each other via one or more Ethernet links, and communications between electronic devices are performed on the Ethernet link using the AVB to transmit and receive various information such as multimedia, controls, diagnoses, and detection information.
FIG. 1 is an exemplary diagram of a vehicle network system in which an Ethernet AVB is connected to an existing vehicle network and a gateway switch, and FIG. 2 is an exemplary view illustrating a message frame format of the Ethernet AVB and a transmission/reception method.
As shown in FIG. 1, the Ethernet AVB is connected to a vehicle network such as CAN, LIN, or FlexRay via a gateway switch and a plurality of messages whose data sizes are substantially small may be integrated in one Ethernet message to be transmitted. Further, destination nodes of vehicle network messages (containing information transmitted from devices) contained in the Ethernet message are different, the Ethernet message should be transmitted to a plurality of nodes (e.g., the devices of the vehicle which transmit and receive the messages) and the nodes that have received the message should extract messages required by the nodes from the plurality of vehicle network messages to use the extracted messages.
Related standards for transmitting vehicle network messages to an Ethernet AVB in a vehicle network such as CAN, LIN, and FlexRay are defined in IEEE 1722a. In other words, a frame format for CAN messages in a draft version of IEEE 1722a includes an AVB header and a plurality of CAN messages, and then, each of the messages include a timestamp value that represents a time point when the message is received in unit of ns. Further, all nodes in the Ethernet AVB are time synchronized according to IEEE 802.AS, and the gateway switch of FIG. 1 may receive a message from LIN, CAN, and FlexRay, and then may transmit a plurality of messages while the plurality of messages are contained in one Ethernet AVB frame as shown in FIG. 2. In particular, since the Ethernet has an overhead for a header, it is efficient to transmit data while maximizing the size of the data.
When a plurality of CAN messages, which are to be transmitted to node 1 and node 2 of FIG. 1, are included in one Ethernet AVB frame according to the related art, the same Ethernet AVB message should be transmitted to all nodes. Thus, since node 1 receives unnecessary information of node 2, a bandwidth of the network is wasted and the nodes that received the unnecessary information generate an overhead of extracting information required by the nodes in the Ethernet AVB message.
Moreover, when a destination of one Ethernet AVB frame includes only one message which is a specific node, a plurality of small Ethernet AVB frames should be transmitted, causing an overhead. Further, the Ethernet of a vehicle should be used in conjunction with existing representative vehicle networks such as LIN, CAN, and FlexRay. In particular, a gateway switch related technology of using a gateway switch shown in FIGS. 1 and 2, and transmitting one Ethernet message while one or more vehicle network messages such as a CAN message whose frame size is substantially small are included in the Ethernet message has been suggested. Further, a frame format by which a vehicle network message transmitted via CAN, LIN, and FlexRay may be included in the Ethernet message of a vehicle is opened in an IEEE 1722a draft version.
Hereinafter, a vehicle network message in the specification refers to a message transmitted by devices connected to vehicle networks such as LIN, CAN, and FlexRay, and nodes (node 1 to node n) connected to an Ethernet switch. In particular, the devices connected to LIN, CAN, and FlexRay and the nodes connected to the Ethernet switch may be controllers in the vehicle which communicate with each other. The vehicle network messages include information to be transmitted and received between the controllers, and include information (e.g., addresses or identification symbols and the like) of dispatch locations and destinations of the messages. Currently, the Ethernet switch technology has been developed in Internet technologies and industrial network technologies, and since only the Ethernet has been considered in the industrial field, the Ethernet switch generally transfers a corresponding message to a destination port based on a MAC address.
As shown in FIG. 2, five vehicle network messages are included in one Ethernet message, and when messages 1 and 3 are to be transferred to node 1, message 2 is transferred to node 3, and messages 4 and 5 are transferred to node 4. However, the existing switch technology does not consider any internal vehicle network messages. Thus, all the Ethernet messages are copied to the nodes to be transferred in the same way. Accordingly, an overhead is generated in the entire network, and the node that received the message analyzes all the Ethernet messages to extract and use messages required by the node.
For example, the Ethernet switch according to the related art switches all the Ethernet frames based on Ethernet MAC addresses, and when the Ethernet is utilized in a vehicle, it needs to be operated in conjunction with the existing vehicle networks such as CAN, LIN, and FlexRay. In particular, an Ethernet message may be transmitted while a plurality of network messages are included in the Ethernet message, and the Ethernet switch performs switching based on a MAC address, a plurality of vehicle network messages to be transmitted only to specific nodes, respectively, should be included in one Ethernet message. In this way, when a plurality of vehicle network messages to be transmitted to nodes of various MAC addresses are included in one Ethernet message, the same message is copied to a plurality of nodes. Accordingly, a bandwidth of a network is wasted and necessary data needs be extracted from all Ethernet messages in each node, generating an overhead.